Valtteri Niemi. Power languages and density. Discrete Applied Mathematics, 32(2):183-193, 1991. [doi]
@article{Niemi91:0, title = {Power languages and density}, author = {Valtteri Niemi}, year = {1991}, doi = {10.1016/0166-218X(91)90099-I}, url = {http://dx.doi.org/10.1016/0166-218X(91)90099-I}, researchr = {https://researchr.org/publication/Niemi91%3A0}, cites = {0}, citedby = {0}, journal = {Discrete Applied Mathematics}, volume = {32}, number = {2}, pages = {183-193}, }